Compression of precipitates in settling vessels.



F. TIEMANN COMPRESSION 0F PBEGIPITATES IN SBTTLING VESSELS.

APPLIOATION FILED 1111. 9, 1911.

1,007,823, Patented N0v.7, 1911.

v FRITZ TIEMANN, OF BERLIN, GERMANY.

COMPRESSION OF PRECIPITATES IN SETILING VESSELS.

Specification of Letters Patent.

Patented Nov. '1, 1911 Application filedv January B, 1911. Serial No. 601,883.

To all whom it may concern:

Be it known that I, FRITZ TIEMANN, director, a subject of the German Emperor, residing at 259 Kurfiirstendamm, Berlin, W., Germany, have invented certain new and useful proyements-in Compression of Precipitate'iiat fiettling vessels; and I do hereby declare the following to be a full, clear, and exact description 0 the invention, such as will enable others skilled in the art to whichit appertains to make and use the same.

It has been proposed to compress preci itates deposited in apparatus generally cal ed settling vessels, more particularly in the case of useful liquids, such as sugar juice, in order to avold the loss of excessive -quantities of useful liquids when. discharging the precipitates from the lower portion of the apparatus =Although the devices were to a certainextentsuccessful, it has hitherto been imfpossible to compress the precipitates to a su cient extent, more particularly those which are partly of organic nature, and therefore very bulky.

The object of this invention is to effect a more perfect compression of the said precipitates, this being attained on the basis of the following considerations.

Bulky precipitates such as for instance those obtained when purifying vegetable juice, on falling down in the settling vessel, inclose pure juice which, lower down in the apparatus, owing to the precipitates forming lumps, is contained in the form of nests. The separation of this juice in an upward direction does not take lace at all, or only imperfectly, as it is inc losed in, the masses which become convertedinto lumps; and on the one hand, the masses settling at the bottom are withdrawn from the circulation of the juice, while on the other hand, the juice masses situated lower down are pre- I vented from rising by the new masses containing new nests of juice continuously sinking down from the top. The object of this process is therefore to shift the downward juice discharge into the lower places, namely with speed reduced in sta es by means of separating bells arranged in stages, and to enable an upward circulation of juice to take place in order freely to discharge the pure juice contained in the nests, through the lumpy masses falling from the top.

Two constructions for carrying out the process according to this invention are illusmit the juice to trated in the accompanying. drawing, in which- Figure 1 is a vertical central section of one apparatus while Fig. 2 isa similar view of a modified apparatus.

0 m Referring particularly to Fig. 1, the same shows 'a settling vessel .or receptacle into which the uice or liquid to be purified is introduced at the top, as by means of an inlet pipe .16. The bottom of the vessel or re-. ceptable is closed under normal conditions; Arranged interiorly of the vessel and disposed in a substantially vertical row, one above the other, are separating bells each having associated therewith an outlet for the purified juice, the outlets passing through the side wallof the vessel at po nts corresponding to the location of the bells. In

the embodiment under consideration there are .four main separating bells T T T T the corresponding juice outlets of which are indicated at A1, A2, A,, A,. These outvices by means of which the speed of the .juice rising in the corresponding bells and passing out of the vessel under the pressure of the liquid in the latter, can be regulated as desired.

Below the lowermost main bell T, is arranged a somewhat smaller bell T and below this, and in comparatively close proximity to the bottom of the vessel is a still smaller bell T These bells are provided with corresponding outlets A A respectively, similar to those previously mentioned and likewise equipped with devices for'regulating the flow of liquid discharged from the vessel at those points.

The operation of an apparatus of this character is substantially as follows: The juice outlets A A A A are so restricted by their closing devices that the juice is permitted to rise in the bells at a speed of say 0.2 mm. per second. Under these conditions the regulating device in connection with the bell T should be adjusted to perrise in the bell not faster than say 0.15 mm. per second, and the lowest bell would be so controlled as to permit the upward movement of the juice at only approximately 0.05 mm. per second. The vessel is filled with liquid up to the inlet E and the juice passes with a certain speed in a downward direction and first reaches the separating bell T The precipitates then lets are equipped with suitable closing -de-' pass downwardaround said bell while the pure juice, by reason of its lower specific the bell to the level of the outlet A,.

' corresponding to the distance from edge of the bell, while the passing ofi of the pure juice under the bell is produced by the gravity, rises in a counter current in. the bell T at the speed previously indicated and is discharged through the outlet A,. It will beunderstood, of course, that the solids or recipitates in the juice passing around the ell T are subjected to a liquid ressure to the relatively slight counter-pressure, which corresponds to the distance from the edge of It will be obvioushow these pressure differences produce a sucking of a portion of the juice out of the nests or lumps of precipitates, and the discharge of purified juice from the bell and from the apparatus. As a portion of thev juice is now removed, the mixture of less juice and proportionately more precipitate passes from the bell T to the bell T led oil at the bell T with less speed, where again a ortion of the rema ning ulce is conducted 0 in a counter current at a speed of approximately 0.2 mm. per second. The discharge speed of the juice in comparison to the speed of the juice passing downward is therefore appreciably i greater than before, by reason of the fact that a portion of the juice has already been juice and slimes [in the main current continues its downward As the mixture of 7' course, it passes the bells T T, with substantially the results previously described.

The precipitates are subjected to a larger andlarger pressure, corresponding to the distance from the level of the liquid, and

. hence as saidprecipitates pass downward the compression of the same continues to increase. On the other hand, the pressure on the pure juice is not substantially increased over that in the bell T owing to the provision of the bells located beneath the latter, the counter-pressure of liquid at each stage of the operation corresponding only to the comparatively short distance between the edge of the corresponding bell and the outlet associated with the latter. Accordingly the proportion of slimes or precipitates in the juice increases ste .by step as the mixture passes from bell to ell, the downlward speed of the juice continually decreasing and the discharge speed of the pure juice contimlallyincreasing with respect to such first named speed. A continually increasing compression of the material separated out is thereby efi'ected, with a corresponding step by step extraction of the juice from the nests or lumps. The comparatively slow discharge speeds used in connection with the lowermost separating bells are necessary because the masses of slimes are highly compressed in the lowerpart of the vessel and therefore contain comparatively little juice.

In view of the necessary small speed of the upward travel of juice, on account of the bulky specifically light reci itates, these settling vessels have to e 0 large diameter.

useful liquid that the vegetab e juice, apart from other damage, would be liable to decomposition. The apparatus shown in Fig. 2 has been designed with a view to obtain the necessary high ressure for compressing- -the precipitates, w ile avoiding the above drawback.

The pressure required for the uppermost main separating bell T for instance one atmosphere, is obtained here by means of stand pipes S between the upper and the 'bottom portions of the apparatus, so that the pressure of about 10 meters of liquid at T requires only a consum tion of 1-2 cubic meters useful liquid, w ile an apparatus such as that shown in Fig. 1, with the same diameter of, say, four meters and also with a pressure of one atmosphere at T would require 125 cubic meters of liquid.

'In the apparatus shown in Fig. 2, juice 'is admitted at E. A,, A,, A, are used for the discharge of pure uice from the main separating bell T and the stage bells T T,, w1th a speed reduced in stages to the desired degree. L is used for discharging the air, and D for removing the scum rising upward. The removal of the precipitates is efiected in both apparatus at the bottom through N as soon as-the precipitates are 'sufliciently compressed by the exhausting 'ofthe nests of juice.

-Having now particularly described and aseertainedthe nature'of mysaid invention and in what manner thesame is to be performed, I declare that what I claim is 1. The herein described method of compressing precipitates' in settlin vessels, which'consists in establishing a ownward current of liquid in which the pressure gradually increases toward the bottom of the vessel, whereby the pressure on the descending solids or precipitates is gradually increased. and establishing counter currents of liquid in the main current and discharging the counter currents at different points in the height of the vessel, substantially as described.

2. The herein described method of compressing precipitates in settling vessels,

which consists in creating a downward current of liquid in a settling vessel, whereby the pressure on the descending precipitates or slimes is continuously increased, and establishing rising counter currents in the main current, whlch carry off the purified liquid from the vessel at different points, substantially as described.

3. The herein described method of compressing precipitates in settling vessels, which consists in establishing a main downward current of the liquid in the vessel, inducing upward counter currents at different points in the length of the main current, and carrying off from the vessel at predetermined speeds the pure liquid in the rising counter currents, substantially as described.

4. The herein described method of compressing precipitates in settling vessels, which consists in establishing a downward flow or current of liquid in the vessel, inducing rising counter currents at different points in the height of the vessel, said counter currents being established one above the other and carrying ofi the rising pure liquid to the exterior of the vessel, and suitably regulating the speed of the several discharge currents of liquid, substantially as described.

5. The herein described method of compressing the precipitates in settling vessels, which consists in establishing a mam downward current of the liquid in the vessel, whereby the pressure on the descending slimes or precipitates is continuously increased, and inducing an upward countercurrent in close proxlmity to'the bottom of the vessel, which counter current carries oil from the vessel the liquid extracted by pressure from the precipitates in the bottom of the vessel, substantially as described.

6. The herein described method of compressing precipitates in settling vessels, which consists in establishing a main downward current of the liquid in the vessel,

whereby the slimes or precipitates descending in the vessel are contlnuousl compressed in an increasing ratio, an establishing in such main current a vertical series of rising currents which carry off the pure liquid from the vessel, one of such counter currents being produced in close proximity to the bottom of the vessel in order to carry oif the pure liquid extracted by pressure from the slimes at the extreme botom portion of the vessel, the speed of ing counter currents of liquid being controlled in a predetermined stantially as described.

In testimony whereof I have aflixed my signature, in presence of two witnesses.

' FRITZ TIEMANN. Witnesses:

WOLDEMAR HAUPT, ARTHUR SOHROEDER.

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